[NMR analysis blog] Alignment of NMR spectra – Part VI: Reaction Monitoring (II)
Alignment of NMR spectra – Part VI: Reaction Monitoring (II)
Previous posts on this series:
Alignment of NMR spectra – Part I: The problem
Alignment of NMR spectra – Part II: Binning / Bucketing
Alignment of NMR spectra – Part III: Global Alignment
Alignment of NMR spectra – Part IV: Advanced Alignment
Alignment of NMR spectra – Part V: Reaction Monitoring (I)
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02-10-2011 08:29 PM
[NMR analysis blog] Alignment of NMR spectra – Part V: Reaction Monitoring (I)
Alignment of NMR spectra – Part V: Reaction Monitoring (I)
Previous posts on this series:
1. Alignment of NMR spectra – Part I: The problem
2. Alignment of NMR spectra – Part II: Binning / Bucketing
3. Alignment of NMR spectra – Part III: Global Alignment
4. Alignment of NMR spectra – Part IV: Advanced Alignment
Following the progression of chemical reactions by NMR is becoming more and more popular. Quoting Michael A. Bernstein et al. (Magn. Reson. Chem. 2007; 45: 564–571)
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02-08-2011 08:16 PM
[NMR analysis blog] Alignment of NMR spectra – Part IV: Advanced Alignment
Alignment of NMR spectra – Part IV: Advanced Alignment
Previous posts on this series:
Alignment of NMR spectra – Part I: The problem
Alignment of NMR spectra – Part II: Binning / Bucketing
Alignment of NMR spectra – Part III: Global Alignment
As I mentioned in my previous post, simple alignment based on shifting or referencing the whole spectrum is not enough in cases where there are different local chemical shift fluctuations.
Resorting back to the synthetic data set used in the previous posts, let me introduce a semi-automatic method designed specifically to align spectra having...
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02-07-2011 07:53 PM
[NMR analysis blog] Alignment of NMR spectra – Part III: Global Alignment
Alignment of NMR spectra – Part III: Global Alignment
Previous posts on this series:
Alignment of NMR spectra – Part I: The problem
Alignment of NMR spectra – Part II: Binning / Bucketing
We have seen that binning helps in minimizing, for example, the effect of pH-induced fluctuations in chemical shift so that, in the field of NMR-based metabonomics studies, ensuring that signals for a given metabolite appear at the same location in all spectra. One evident disadvantage of binning is that it greatly reduces the spectral resolution (e.g. in a 500 MHz instrument, a typical 64 Kb...
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02-03-2011 06:51 PM
[NMR analysis blog] Alignment of NMR spectra – Part II: Binning / Bucketing
Alignment of NMR spectra – Part II: Binning / Bucketing
In my last post, I wrote that spectra of biological samples are usually poorly aligned due to wide changes in chemical shift arising from small variations in pH or other sample conditions such as ionic strength or temperature.
The most widely used method of addressing this chemical shift variability across spectra is by means of the so-called binning (or bucketing), procedure that consists in segmenting a spectrum into small areas (bins / buckets) and taking the area under the spectrum for each segment. Preferably, the size of the...
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01-31-2011 06:03 AM
[NMR analysis blog] Alignment of NMR spectra – The problem: Part I
Alignment of NMR spectra – The problem: Part I
The chemical shift is of great importance for NMR spectroscopy because it reflects the chemical environment of the nuclides under observation providing detailed information about the structure of a molecule.
Although the chemical shift of a nucleus in a molecule is generally assumed to be fairly stable, there are a number of experimental factors (pH, ionic strength, solvent, field inhomogeneity –bad shimming, temperature, etc) which might produce slight or even quite significant variations in chemical shifts.
This is particularly important...
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01-28-2011 04:52 AM
[NMR paper] Partial alignment of biomolecules: an aid to NMR characterization.
Partial alignment of biomolecules: an aid to NMR characterization.
Related Articles Partial alignment of biomolecules: an aid to NMR characterization.
Curr Opin Chem Biol. 2001 Oct;5(5):584-90
Authors: Prestegard JH, Kishore AI
Partial alignment of biomolecules in solution has added a new dimension to structural investigation by high-resolution NMR methods. Applications to proteins, nucleic acids and carbohydrates now abound. Limitations initially associated with compatibility of biomolecules with the liquid-crystal media commonly used to...
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11-19-2010 08:44 PM
alignment in a magnetic field
hi all,
I have a general question about alignment in a magnetic field.
For me, alignment in alignment media is easier to grasp because of interactions that I am familiar with as a chemist.
But, whats the principle behind molecules that align in a magnetic field?
There are a lot of examples like cyanometmyoglobin (from the Prestegard paper) where paramagnetic susceptibility plays a role. Thats understandable from my side.
But what about for instance short DNA dimers (helices), collagen gels or bacteriophages?
I could not really find a nice (clear to me) explanation, why these...